The present invention relates to a light barrier for the monitoring of a light path having a base assembly of a first transmitter emitting a light signal and a first receiver generating an output signal for a control. The present invention in particular relates to light barriers for the control of door drives.
It can be detected by such a light barrier whether an object is located in the monitored light path in that a check is made using the receiver whether the object is blocking the light signal emitted by the transmitter or not. The receiver of the base assembly evaluates the irradiated light signal and provides a corresponding switch signal at a control output. In this respect, both an operating principle with a static output signal and a dynamic principle are possible.
Known light barriers are either designed as one-way light barriers, with the transmitter being arranged on one side of the light path to be monitored and the receiver directly irradiated by it being arranged on the other side. Alternatively to this, reflection light barriers are used in which the light emitted by the transmitter of the base assembly is reflected via a passive reflector back to the receiver of the base assembly. Such reflection light barriers are easier to install and can be manufactured more cost-effectively, but have a lower safety level due to possibly occurring erroneous reflection and their range is therefore limited.